I built myself a watercooled Peltier-based Cloud chamber, because I had an AIO Watercooler for a PC laying around.
In my case it is an Enermax III Liqmax RGB with a 240mm Radiator. The radiator is screwed in with 2x M3.5 screws along the support beams, it holds up very well and does not shake or anything.
Obviously you will need some stuff from the hardware store, in my case a M4 threaded rod that I cut to the right length, corresponding washers and nuts. The hole pattern I used to correctly align the 3D-printed parts with the waterblock was the AM4 standard.

The soldered "electronic" part is all internal in the space under the pump-block. I used pin-strips to connect the fans and pump to 12V (as I did not want to cut the cables of the AIO. This also would enable me to use it again in a PC build if I ever wanted.).
Main power for the Peltiers (3 stacked, a "TEC-12709" that is getting 12V at the bottom, and 2x "TEC-12706" that are recieving 5V in the middle, and 3.3V on top) comes from 3x4mm Banana-Sockets and leaves through one common ground.
All in all the systen consumes ~100W and reaches a temperature of about -25C at the cold plate. The radiator is of course way overkill so it does not even get warm.

The top plate has a cutout for a 50x50x1mm copper plate to press down on the Peltier modules so they make good contact, as well as for increasing the surface of the viewable area a little bid. I used 0,5mm thick thermal pads from Arctic, as thermal paste can be quite a mess to get right.

I hope this inspires someone to build it for themselves, it was a really cool and fun project and works well! In the Photo you can see an Alpha particle as well as some Beta particles.
Any questions? Leave a comment!

PS: If your printer is big enough, you can of course print the “combined_base” and you will not need the connector piece :)